1. Field of the Invention:
The present invention relates to a chip-type electronic element supplying apparatus for use in an apparatus for automatically mounting chip-type electronic elements on a printed circuit board.
2. Related Art Statement:
Chip-type electronic elements 1, formed variously as shown in FIGS. 12A to 12D are accommodated in recessed portions 2a formed in a carrier tape 2 which has conveyance holes 3 formed at predetermined intervals on either side of the carrier tape 2 as shown in FIG. 13. Thus, a taped electronic element group 5 is supplied to a user in a state where it is covered with a cover tape 4 and wound around a reel 6. The apparatus (omitted from illustration) for automatically mounting electronic elements is an apparatus arranged to sequentially take out the chip-type electronic elements 1 from the reel 6 so that they are then mounted on a circuit board. The chip-type electronic element supplying apparatus is a portion of the above-described apparatus for automatically mounting electronic elements.
FIG. 14 is a perspective view which illustrates a related-art chip-type electronic element supplying apparatus. Referring to FIG. 14, a carrier tape 2 taken out from the above-described reel 6 is guided to a feeding ratchet 25 so that a multiplicity of hooking claws 26 secured to the above-described feeding ratchet 25 are sequentially fastened to conveyance holes 3 formed in the carrier tape 2 when the feeding ratchet 25 is rotated. The carrier tape 2 is conveyed while being guided along the feeding ratchet 25 by a tape retainer 22 disposed above the feeding ratchet 25. The above-described cover tape 4 is turned by an angle of about 180.degree. and is taken out in a direction opposite to the direction in which the carrier tape 2 is fed, at a position of a slit D formed in a slightly upstream (adjacent to the reel 6) of an opening portion C which is formed in the above-described tape retainer 22 and through which the electronic elements are taken out so that the cover tape 4 is separated from its carrier tape 2. The leading portion of the separated cover tape 4 is wound around a take-up reel 27.
The above-described opening portion C, through which the electronic elements are taken out, is opened when a shutter 20 is moved in a direction designated by an arrow Y.sub.2 which opposes a direction designated by an arrow Y.sub.1 via a reverse-rotation lever 11 disposed between a feeding lever 28 and the shutter 20 by an action of a kicker (omitted from illustration) provided for the apparatus (omitted from illustration) for automatically mounting electronic elements in synchronization with the action of the apparatus for automatically mounting electronic elements. That is, the above-described shutter 20 is movably fastened to the tape retainer 22 in such a manner that the shutter 20 covers the opening C through which the electronic elements are taken out when the feeding lever 28 is pulled in the direction Y.sub.2 by a tension spring 32. A feeding ratchet lever 14 connected to the above-described feeding lever 28 by a connection pin 13 and arranged to act in synchronization with the action of the feeding lever 28 is moved downwards. As a result, a feeding ratchet claw 16 fastened to the feeding ratchet lever 14 via a supporting point 15 is returned by one pitch in a direction which opposes the direction of the rotation of the above-described feeding ratchet 25.
When the above-described feeding lever 28 is moved in the direction Y.sub.1, a movable lever 18 having a supporting shaft 17 which is commonly used as the supporting shaft for the feeding lever 28 is upwards moved via a connection pin 19. Then, a take-up ratchet lever 35 is upwards moved around a rotational shaft 30 of the above-described take-up reel 27 by a connection rod 24 which establishes a connection between the movable lever 18 and the take-up ratchet lever 35. As a result, a take-up ratchet claw 23 fastened to the ratchet lever 35 via a supporting point 36 is returned by one or plural pitches in a direction which opposes a direction in which the take-up ratchet 29 is rotated.
In the above-described state in which the opening portion C through which the electronic elements are taken out is opened, an operation of adsorbing the electronic elements and an operation of mounting the same on the printed circuit board (omitted from illustration) are performed by a vacuum adsorbing head (omitted from illustration). Since, the above-described manufacturing process is not relevant to the structure of the chip-type electronic element supplying apparatus, this process is omitted here.
When the pushing force given to the feeding lever 28 from the above-described kicker is released in a state shown in FIG. 14, the feeding lever 28 is returned in the direction Y.sub.2 by the urging force of the tension spring 32. As a result, the feeding ratchet lever 14 is moved upwards and the feeding ratchet claw 26 upwards pushes the feeding ratchet 25 in synchronization with the above-described upward movement of the feeding ratchet lever 14 so that the feeding ratchet 25 is rotated by a predetermined number of pitches in the tape feeding direction. Then, the hooking claw 26 secured to the feeding ratchet 25 conveys the carrier tape 2 by a predetermined number of pitches in the direction Y.sub.1. At this time, the shutter 20 is, similarly to the carrier tape 2, moved in the direction Y.sub.1 via the reverserotation lever 11. As a result, a state where the opening portion C through which the electronic elements are taken out is covered by the shutter 20 is realized. Therefore, the carrier tape 2 is moved in a state where the above-described electronic elements 1 are covered with the shutter 20. As a result, undesirablc pop-out of the chip-type electronic elements 1 from the recessed portions 2a of the carrier tape 2 can be prevented.
On the other hand, the take-up ratchet 29 is rotated in a direction designated by an arrow shown in FIG. 14 by the take-up ratchet claw 23 when the above-described feeding lever 28 is returned. The cover tape 4 separated at the slit D is wound by a take-up reel 27 to which the feeding ratchet 29 is secured by a predetermined length (a length corresponding to a predetermined pitch of feeding of the carrier tape 2). At this time, the movable lever 18 is downwards moved when the feeding lever 28 is returned in the direction Y.sub.2. During the above-described movement process, the movable lever 18 is given the urging force determined by the tension spring so as to keep an interval from the connection pin 19.
As described above, the structure is constituted in such a manner that predetermined rotational force is always given to the take-up reel 27 by the tension spring 31 via the connection rod 24, the take-up ratchet claw 23 and the take-up ratchet 29 to separate the cover tape 4.
Furthermore, the reel 6 is inserted into the supporting shaft 8 provided for the body cover 7 so as to be held by a leaf spring 9 from the side surface. Therefore, the horizontal deviation of the reel 6 is prevented and the reel 6 is stably held so that the looseness of the carrier tape 2 taken place at the time of feeding thereof is prevented. Reference numeral 10 represents a front cover, 21 represents a carrier tape receiving plate and 12 represents a carrier tape discharge port.
Recently, there is a desire of reducing (in particular, reducing the space between the supply apparatuses) the thickness of the chip-type electronic element supplying apparatus in order to improve the mounting tactic of the apparatus for automatically mounting electronic elements. Therefore, the related-art chip-type electronic element supplying apparatus constituted as shown in FIG. 13 encounters a problem in that there is a limit present in reducing the thickness of the supply apparatus due to the unsatisfactory rigidity of the body of the supply apparatus and thereby the electronic elements cannot be stably supplied.